This invention relates in general to apparatus for illuminating an eye undergoing eye surgery and, more specifically, to an apparatus for illuminating an eye by lamellar illumination, combining scleral scatter and retroillumination, during surgery such as radial keratotomy, astigmatic keratotomy, cataract removal and the like.
Conventionally, coaxially operating room microscope illumination is used to view the surgical field during eye surgery. Because of observed phototoxic effects of coaxial illumination, various filters or light-dimming techniques have been developed to reduce those effects. Still, the operating room microscope places significant light coaxial to the patient's visual axis, which can result in retinal phototoxicity, patient discomfort and corneal drying.
Illumination approaching perpendicular enters the eye directly through the pupil and stimulates the most sensitive back surface of the eye. This results in a patient sensation of extreme brightness, associated discomfort and tearing.
Axial lighting requires high levels of illumination and the reflected light image must compete with the glare from the projected light. The surgeon can experience difficulties during a procedure with glare that emanates from the axial light source reflecting from the anterior surface of the eye or associated structures and instrumentation.
The high intensity of axial light is often associated with a drying effect on the anterior structures of the eye secondary to a drying effect on the tear film. This drying can alter the thickness of the cornea and health of the surface tissue of the cornea (corneal epithelium), which in the setting of refractive surgery can result in serious surgical errors and complications. Further, phototoxicity of the posterior structures of the eye (retina) can occur with the use of strong axial microscope lighting and can cause permanent vision loss.
Thus, there is a continuing need for improved eye illumination apparatus which reduces light intensity, reduces drying effects to the eye decreases the light reaching the back of the eye to reduce patient discomfort and essentially eliminate phototoxicity, reduces glare and light reflected back into the microscope ocular, and provides improved visualization of the surgical field and instrument position.